A common style of window construction has a first framed pane of glass (the sash) mounted within a larger frame (herein referred to for convenience as the master frame) in such a way that the sash is slidable between open and closed positions within the master frame. Typically, adjacent horizontal members of the sash frame and master frame are provided with slidably engaging tongue-and-groove style projections and recesses to define and support the sliding movement of the sash within the master frame. By adjusting the dimensions of the sash frame and master frame, this construction can also be used to provide doors, such as sliding patio doors.
A known technique for constructing frame assemblies for windows or doors is to extrude sections of aluminum or vinyl having a desired cross-sectional profile for the various vertical and horizontal members of the frames. The extrusions are then cut to length, and the sash frame is fully assembled, while the master frame is only partially assembled. The sash frame can then be slid into the partially assembled master frame, after which assembly of the master frame can be completed. An example of known extrusion profiles for constructing window frames can be seen in U.S. Pat. No. 4,621,478 (Phillips et al.).
Another frame construction for a sliding window is disclosed in U.S. patent application Ser. No. 09/735,498, having Publication No. US 2002/0124494 (Zen). This frame construction has a two-piece master frame, between which a sash frame is sandwiched. The sash comprises two injection molded halves which are secured together with fasteners. The assembled sash is positioned between two halves of the master frame, each of which are also separate, injection molded elements, secured together with fasteners.
The construction techniques described above can be relatively time-consuming and costly. Also, if the assembly is improperly performed, problems with the function or appearance of the product may result. Accordingly, it may be advantageous to provide a frame assembly for a window or door wherein the master frame and sash frame are each integrally molded, one-piece structures.